Tire-mold.



rations as it .unirse sacarse ALBERT HARGRAVES, OF AKRON, OHID, ASSIGNOR T0 THE EIRESTONE TIRE AND RUBBER COMPANY, OF AKRON, HO, A CORPORATON 0F lrl'.

TIRE-MOLD.

Lasarte,

To all whom t may concern:

Be it known that l, Annnn'r Hnnoimvns, a subject ofthe King' of Great Britain, residing in the city of Akron, county ot' Summit, State of Ohio, have invented certain new and useful Improvements in 'idro-Molds, of which the following is a specification.

In the manufacture of automobile and truck tires it is often desirable to make use of a mold equipped with a multiple-part tread ring provided with inclined outer surfaces designed to cooperate with correspondingly inclined surfaces on the inner sides of the mold cavity whereby, when the mold is closed, the ring is caused. to contract and pressure thereby exerted on the tread portion of the tire as is well understood by those skilled in the art. This construction is par ticularly useful in the manufacture of tires having irregular' or indented tread configucauses the irregularities or in* dentations to be better and more accurately formed.

)In former constructions of this nature it frequently happens that sections of the ring' will get out of alinernent which results in a badly formed tire and is liable to injure the mold. 'l'he cmstruction herein shown has been devised to insure the centering and ac curate positioning of the mold ring` sections, the particular design shown being for the manufacture ot' large solid tires which are grooved in the tread in accordance with the showing in the Patent to Lee Clough No. 1,268,437, dated June l, 1918, although its usefulness is not limited to this construction.

in the drawings Figure 1 is a plan view ot half of the mold with the tread ring in place.

Fig. 2 is a cross section on the line 2 2 of Fig. l.

In the drawings 1 represents the upper half of the inold and 2 the lower halt'. In each half of the mold is provided a cavity 3 ot' the shape ot' the side of the tire and a seat 4 for an internal ring 5. Near the outer edge of the mold is provided an inclined seat (i and in the two seats is adapted to be placed the multiple-part tread ring 7, the outer surfaces, except for the central portion, being inclined to correspond to the inside of the cavity so that as the mold is closed under pressure the ring will contract. The inner surface is shaped to conform to the finished product in this instance being provided with Specification of Letters Patent.

rammen nea si., Serial No. 235,861.

ribs 13 to form the circumferential groove in the surface of the tire. Around the center ot the tread ring is formed a rib 8 which is adapted to seat on the shoulders 9 on the in side of the mold. It is by means of this rib and shoulders that the ring is accurately seated in the mold. At each side of the treafl ring are provided cavities for the overflow. as

at 10, and between sections of the ring are.

provided additional' overflow cavities 11.

rthe mold is assembled by first placing the tire 12 and Ithe ring 5 in the lower half. The sectional tread ring, which may be in three or more parts, is then placed around the outside ot' the tire` the seat (5. The upper part of the mold is now placed and the sectional tread ring seated partially in the cavity. rThe two parts of the mold are then forced together and the ring is seated as shown in Fig. 2. lt will be seen that the rib 8causes the parts of the ring to be accurately seated in the mold', so that when the mold is closed the tread ring is suspended midway between the tire mold sections whereby the entrances to the overfiow cavities are maintained open and the overflow is equally divided above and below the center of the tire, and the ribs are forced into the tire whereby the grooves are formed.

It is obvious that changes and modifications may'be made in the design of the mold without departing from the spirit of the invention or sacrificing any of its benefits.

I claim:

1. In a tire mold, the combination oi"- nptread mold,

lions, overtlowcavities, entrances to said cavities being provided between said mold sections and said ring, mating projections and recesses between said sections and said ring, adapted to position said ring, whereby and part way down into the entrances to said cavities are maintained unobstructedwhen the mold is closed.

In a tire mold, the combination of upper and lower mold sections, a separate sectional tread ring between the two sections, overflow cavities, entrances to said cavities being provided at the upperand lower sides of said tread ring, inclined 'surfaces on the outside of the tread ring and coperating inclined surfaces on the inold sections, and a mating projection and recess in the ring and mold adapted to position said ring when the mold is closed'so that the entrances to said cavities are maintained open when the mold is closed.

, 4. `In a tire mold, the combination of upper and lower mold sections, a separate sectional tread ring between the two sections,

-overow cavities, inciined surfaces on the outsidef the tread ring and coperating inclmed surfaces on the mold sections, a rib on the center of said tread ring, one of the mold sections being provided with a recess adapted to receive said rib, the inside upper and lower edges of said ring being spaced from said mold sections when the mold is closed, saidring lbeing suspended in said mold b v the rib, whereby there are provided spaces ai' the sides of said ring, the said spaces coinmunicating with said overflow cavities.

5. ln a tire mold, the combination of upper and lower mold sections, a separate tread ring between the two sections of ythe meld, overfiow cavities in the mold sections, entrances to said cavities being provided at the' sides of said ring, a rib on said ring adaptedf i to be received between said mold -sections and to support the ring on the lower section, whereby the entrances to said cavities are maintained unobstructed when the mold is closed.

ALBERT HARGRAvEs 

